scholarly journals Ontogenetic niche shifts in dinosaurs influenced size, diversity and extinction in terrestrial vertebrates

2012 ◽  
Vol 8 (4) ◽  
pp. 620-623 ◽  
Author(s):  
Daryl Codron ◽  
Chris Carbone ◽  
Dennis W. H. Müller ◽  
Marcus Clauss
Keyword(s):  
Postnatal Ontogeny ◽  
Terrestrial Vertebrates ◽  
Terrestrial Vertebrate ◽  
Physiological Limits ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Size Diversity ◽  
Intermediate Size ◽  
The Impact ◽  
Land Vertebrates

Given the physiological limits to egg size, large-bodied non-avian dinosaurs experienced some of the most extreme shifts in size during postnatal ontogeny found in terrestrial vertebrate systems. In contrast, mammals—the other dominant vertebrate group since the Mesozoic—have less complex ontogenies. Here, we develop a model that quantifies the impact of size-specific interspecies competition on abundances of differently sized dinosaurs and mammals, taking into account the extended niche breadth realized during ontogeny among large oviparous species. Our model predicts low diversity at intermediate size classes (between approx. 1 and 1000 kg), consistent with observed diversity distributions of dinosaurs, and of Mesozoic land vertebrates in general. It also provides a mechanism—based on an understanding of different ecological and evolutionary constraints across vertebrate groups—that explains how mammals and birds, but not dinosaurs, were able to persist beyond the Cretaceous–Tertiary (K–T) boundary, and how post-K–T mammals were able to diversify into larger size categories.

Bimodal population size distributions and biased gillnet sampling

2004 ◽  
Vol 61 (11) ◽  
pp. 2151-2157 ◽  
Author(s):  
Anders Gravbrøt Finstad ◽  
Ole Kristian Berg
Keyword(s):  
Sampling Method ◽  
Salvelinus Alpinus ◽  
Size Difference ◽  
Size Distributions ◽  
Abrupt Increase ◽  
Bimodal Size Distribution ◽  
Lower Mode ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Intermediate Size

Bimodal size distributions have been commonly observed in Arctic char (Salvelinus alpinus). We document an example of such bimodality caused solely by biased gillnet sampling. The observed bimodality was a direct artefact of the sampling method resulting from an abrupt increase in gillnet catchability of fish larger in total length than between 25 and 30 cm. Mean gillnet selectivity (catchability) of char in the upper mode of the observed bimodal size distribution was about 40 times higher than the corresponding value for char in the observed lower mode. Fish of intermediate size, lacking in the gillnet samples, were present in the population and readily obtainable by electrofishing. The observed size difference in gillnet vulnerability is likely to result from behavioural changes following ontogenetic niche shifts.

scholarly journals Impact of Environmental Stressors on Gene Expression in the Embryo of the Italian Wall Lizard

2021 ◽  
Vol 11 (11) ◽  
pp. 4723
Author(s):  
Rosaria Scudiero ◽  
Chiara Maria Motta ◽  
Palma Simoniello
Keyword(s):  
Gene Expression ◽  
Protein Interactions ◽  
Membrane Trafficking ◽  
Translational Regulation ◽  
Cellular Protection ◽  
Terrestrial Vertebrate ◽  
Expression Of Genes ◽  
Stress Changes ◽  
Probable Consequence ◽  
The Impact

The cleidoic eggs of oviparous reptiles are protected from the external environment by membranes and a parchment shell permeable to water and dissolved molecules. As a consequence, not only physical but also chemical insults can reach the developing embryos, interfering with gene expression. This review provides information on the impact of the exposure to cadmium contamination or thermal stress on gene expression during the development of Italian wall lizards of the genus Podarcis. The results obtained by transcriptomic analysis, although not exhaustive, allowed to identify some stress-reactive genes and, consequently, the molecular pathways in which these genes are involved. Cadmium-responsive genes encode proteins involved in cellular protection, metabolism and proliferation, membrane trafficking, protein interactions, neuronal transmission and plasticity, immune response, and transcription regulatory factors. Cold stress changes the expression of genes involved in transcriptional/translational regulation and chromatin remodeling and inhibits the transcription of a histone methyltransferase with the probable consequence of modifying the epigenetic control of DNA. These findings provide transcriptome-level evidence of how terrestrial vertebrate embryos cope with stress, giving a key to use in population survival and environmental change studies. A better understanding of the genes contributing to stress tolerance in vertebrates would facilitate methodologies and applications aimed at improving resistance to unfavourable environments.

scholarly journals Predation and associational refuge drive ontogenetic niche shifts in an arctiid caterpillar

Ecology ◽  
2015 ◽  
Vol 96 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Patrick Grof-Tisza ◽  
Marcel Holyoak ◽  
Edward Antell ◽  
Richard Karban
Keyword(s):  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
Associational Refuge

The impact of native competitors on an alien invasive: temporal niche shifts to avoid interspecific aggression

Ecology ◽  
2009 ◽  
Vol 90 (5) ◽  
pp. 1207-1216 ◽  
Author(s):  
Lauren A. Harrington ◽  
Andrew L. Harrington ◽  
Nobuyuki Yamaguchi ◽  
Michael D. Thom ◽  
Pablo Ferreras ◽  
...  
Keyword(s):  
Interspecific Aggression ◽  
Temporal Niche ◽  
Niche Shifts ◽  
The Impact

scholarly journals Initial terrestrial vertebrate diversity assessment in upland Cavite, Philippines

2019 ◽  
Vol 12 (2) ◽  
Keyword(s):  
Diversity Index ◽  
Conservation Status ◽  
Wildlife Habitat ◽  
Direct Result ◽  
Forest Fragments ◽  
Terrestrial Vertebrates ◽  
Terrestrial Vertebrate ◽  
Wiener Diversity Index ◽  
Diversity Assessment ◽  
Animal Diversity

Cavite’s remaining upland forest fragments are either remnant from commercial logging activities ca. 25-45 years ago or as a direct result of land conversions for agriculture or human settlements. These forest fragments are very significant because they represent areas where pockets of wildlife habitat still remain. The terrestrial vertebrates are often used to assess animal diversity because they are ideal biological indicators of environmental change and anthropogenic disturbances. The study aimed to determine terrestrial vertebrate diversity, conservation status, and identify major anthropogenic threats in these fragments. Terrestrial vertebrates were surveyed using a combination of strip-transect sampling, time-constrained searches, visual encounter survey (VES), and acoustic encounter survey (AES; for amphibians only), point counts, live trapping and mist netting from October 2014 to March 2016. Species richness and biodiversity estimation were computed using Shannon-Wiener Diversity Index, linear regression, detection and probability modeling using PAST, and confidence limits for nestedness (0.05α) using EpiTools. A total of 175 terrestrial vertebrates were documented and among the vertebrate groups, the birds had the highest observed diversity. Twenty-nine (19 birds, 3 mammals, 3 lizards, and 4 anurans) species are listed as threatened. Habitat loss and degradation due to the conversion of habitats to agricultural and/or residential areas remained to be the most prevalent threat in the remaining forested areas in upland Cavite. Baseline data generated shall be used in the different government biodiversity monitoring activities as the basis for impacts and mitigation and initial planning for the management and conservation of these remaining forest patches.

The Impact of Breed, Testing Time and Metabolic Profile on the Variation of Copper Concentration in Sheep Blood Serum

2021 ◽  
Author(s):  
J. Autukaitė ◽  
V. Juozaitienė ◽  
R. Antanaitis ◽  
I. Poškienė ◽  
W. Baumgartner ◽  
...  
Keyword(s):  
Copper Concentration ◽  
Testing Time ◽  
Blood Parameter ◽  
Monthly Basis ◽  
Limit Values ◽  
Blood Samples ◽  
Average Value ◽  
Physiological Limits ◽  
Blood Biochemical ◽  
The Impact

Background: Copper supplementation in ruminants deserves special attention because of the narrow margin between deficiency and toxicity. The aim of the study was to analyse the relationship between the Cu concentration and other blood parameter values having taken into consideration their physiological limits based on the variation of copper concentration in the three different sheep breeds. Methods: Sixty sheep (35±5 kg) kept on the same farm were studied: the Suffolk (n = 20), the Merino (n = 20) and the Lithuanian blackhead (n = 20). The sheep were selected according to the following parameters: 3.5±0.3 years old, not pregnant during the entire investigation period, clinically healthy. All sheep were kept under the same conditions and throughout the year, were fed at the same time the same ration balanced according to their physiological needs. Individual blood samples were collected on the same day, on monthly basis for the period of one year (April 2018 to May 2019). Blood biochemical parameters as well blood haematology and cortisol concentration were analysed.Result: The highest average value of copper concentration was found in the Merino breed. The study has shown that the lowest number of blood samples with the levels of copper meeting the physiological limit values was found in the native Lithuanian blackhead sheep at the end of the grazing period and in the Merino and the Suffolk breeds - during the coldest winter months. The increase in copper concentration could be related to the stress caused due to the changes in dietary conditions, the variations of ambient temperature and different breed response to these factors.

Ontogenetic Niche Shifts, Predators, and Coexistence among Consumer Species

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Alternative Stable States ◽  
Niche Partitioning ◽  
Stage Structure ◽  
Stable States ◽  
Stable Coexistence ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
Dependent Growth ◽  
Equal Population

This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, and how ontogenetic niche shifts may give rise to alternative stable states. More specifically, the analysis will use techniques developed within the consumer-resource framework of Tilman (1982), including consumption and renewal vectors (Schellekens, de Roos, and Persson 2010). Tilman showed that stable coexistence between consumers feeding on the same two resources is possible if each consumer species feeds proportionally more on the resource that limits its own growth most. Stable coexistence is, however, also affected by the form of resource-dependent growth isoclines, which represent combinations of resource densities that lead to equal population growth of consumers. It is shown that ontogenetic niche shifts per se affect the form of resource-dependent growth isoclines, which in turn may lead to coexistence through niche partitioning. The chapter also discusses how predation may promote the performance of a species undergoing ontogenetic niche shifts even in the case where it is both the inferior competitor and the preferred prey of the predator.

Ontogenetic Niche Shifts

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Life History ◽  
Extended Model ◽  
Full Model ◽  
Life History Stages ◽  
Ontogenetic Diet Shifts ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Limited Supply ◽  
Diet Shifts ◽  
Parameter Values

This chapter considers the consequences for community structure of ontogenetic diet shifts that involve the use of different resources in different life history stages, whereby these resources are in limited supply and are hence competed for by all individuals foraging on them. It explores the consequences of ontogenetic diet shifts using stage-structured biomass models that account for two basic resources, a stage-structured consumer population, for which we distinguish between juveniles and adults, and up to two unstructured predator populations. The most extended model is therefore closely related to the model analyzed in Chapter 5, except for the inclusion of an additional basic resource. The equations of the full model are summarized and default parameter values are listed.

Summary

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
General Framework ◽  
Community Effects ◽  
Present Volume ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Different Types ◽  
Emergent Community ◽  
Ontogenetic Niche

This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be analyzed as well as provide a clear impression of the results and insights that presented in this book. Topics discussed include biomass overcompensation, ontogenetic (a)symmetry in energetics, emergent community effects of biomass overcompensation, ontogenetic niche shifts in consumer life history, ontogenetic niche shifts in predator life history, competition between consumers with and without ontogenetic niche shifts, and ontogenetic (a)symmetry in energetics and population dynamics.

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